Singapore Chinese Health Study

From the Saw Swee Hock School of Public Health (A.P., W.-P.K.) and Yong Loo Lin School of Medicine (A.P.), National University of Singapore and National University Health System, Singapore, Singapore; Duke-NUS Graduate Medical School, Singapore, Singapore (W.-P.K.); Singapore General Hospital, National Neuroscience Institute, Singapore, Singapore (D.A.D.S.); Division of Cancer Control and Population Sciences, University of Pittsburgh Cancer Institute, PA (J.-M.Y.); and Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, PA (J.-M.Y.).

From the Saw Swee Hock School of Public Health (A.P., W.-P.K.) and Yong Loo Lin School of Medicine (A.P.), National University of Singapore and National University Health System, Singapore, Singapore; Duke-NUS Graduate Medical School, Singapore, Singapore (W.-P.K.); Singapore General Hospital, National Neuroscience Institute, Singapore, Singapore (D.A.D.S.); Division of Cancer Control and Population Sciences, University of Pittsburgh Cancer Institute, PA (J.-M.Y.); and Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, PA (J.-M.Y.).

From the Saw Swee Hock School of Public Health (A.P., W.-P.K.) and Yong Loo Lin School of Medicine (A.P.), National University of Singapore and National University Health System, Singapore, Singapore; Duke-NUS Graduate Medical School, Singapore, Singapore (W.-P.K.); Singapore General Hospital, National Neuroscience Institute, Singapore, Singapore (D.A.D.S.); Division of Cancer Control and Population Sciences, University of Pittsburgh Cancer Institute, PA (J.-M.Y.); and Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, PA (J.-M.Y.).

From the Saw Swee Hock School of Public Health (A.P., W.-P.K.) and Yong Loo Lin School of Medicine (A.P.), National University of Singapore and National University Health System, Singapore, Singapore; Duke-NUS Graduate Medical School, Singapore, Singapore (W.-P.K.); Singapore General Hospital, National Neuroscience Institute, Singapore, Singapore (D.A.D.S.); Division of Cancer Control and Population Sciences, University of Pittsburgh Cancer Institute, PA (J.-M.Y.); and Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, PA (J.-M.Y.).

Abstract

Background and Purpose—Prospective relation between sleep duration and stroke risk is less studied, particularly in Asians. We examined the association between sleep duration and stroke mortality among Chinese adults.

Methods—The Singapore Chinese Health Study is a population-based cohort of 63 257 Chinese adults aged 45 to 74 years enrolled during 1993 through 1998. Sleep duration at baseline was assessed via in-person interview, and death information during follow-up was ascertained via record linkage with the death registry up to December 31, 2011. Cox proportional hazard models were used to calculate hazard ratios with adjustment for other comorbidities and lifestyle risk factors of stroke mortality.

Results—During 926 752 person-years of follow-up, we documented 1381 stroke deaths (322 from hemorrhagic and 1059 from ischemic or nonspecified strokes). Compared with individuals with 7 hours per day of sleep, the multivariate-adjusted hazard ratio (95% confidence interval) of total stroke mortality was 1.25 (1.05–1.50) for ≤5 hours per day (short duration), 1.01 (0.87–1.18) for 6 hours per day, 1.09 (0.95–1.26) for 8 hours per day, and 1.54 (1.28–1.85) for ≥9 hours per day (long duration). The increased risk of stroke death with short (1.54; 1.16–2.03) and long durations of sleep (1.95; 1.48–2.57) was seen among subjects with a history of hypertension, but not in those without hypertension. These findings were limited to risk of death from ischemic or nonspecified stroke, but not observed for hemorrhagic stroke.

Conclusions—Both short and long sleep durations are associated with increased risk of stroke mortality in a Chinese population, particularly among those with a history of hypertension.